The moment Microsoft announced it would lock other browsers out of being installed on Windows RT, we all knew regulatory bodies the world over were wringing their hands. Today, this has been confirmed: in the wake of an investigation into Microsoft not complying with the existing antitrust rulings regarding browser choice, the EU has also announced it's investigating Windows 8 x86 and Windows 8 RT (ARM).

Watch that temper! I think the post you responded to was right, actually. Microsoft isn't forcing consumers to buy ARM machines, but they've already used their power to negatively influence ARM UEFI specs to the detriment of competitors. And there's certainly room for microsoft to pressure ARM OEMS by using their status as a x86 monopoly.

I'm not asserting that they ARE doing it, but clearly they COULD. I am not privy to the backroom deals, but hypothetically MS might give additional x86 discounts to OEMs who bundle only Windows with their ARM products. This is certainly not out of the realm of possibilities and it's clearly within the realm of anti-trust.